Draft gear



H. E. TUCKER Oct. 17, 1.933.

DRAFT GEAR Filed May 16, 1928 4 Sheets-Sheet l kh Q mmm um \w @N Pw n 1/w v H N w \fr l m m t wx H. E. TUCKER Oct. 17, 1933.

DRAFT GEAR Filed May 16 1928 4 Sheets-Sheet 2 Oct. 17, 1933. H. E.TUCKER 1,930,701

DRAFT GEAR Filed May 16, 1928 4 Sheets-Sheet 3 H. E. TUCKER Cet. 17,1933.

DRAFT GEAR 4 Sheets-Sheet 4 Filed May 1e, 1928 Patented Oct. 17, 1933UNITED STATES PATENT OFFICE DRAFT GEAR poration .of Illinois ApplicationMay 16, 1928. Serial No. 278,169

6 l Claims.

The invention relates to draft gears for railway cars and among itsobjects are the securing of high efficiency and durability andto providefor the taking up of wear to the end that efficiency may be maintained.

Further objects will appear in connection with the description of thedevice.

The invention consists in a structure, such as is hereinafter described,and as illustrated in 4the accompanying drawings in which Fig. 1 is acentral, longitudinal plan section;

Fig. 2 is a detail in plan of the central wedging system and centralfriction element of the gear; Y

Fig. 3 is a detail sectional view on the line 33 of Fig. 1;

Fig. 4 is a sectional view in part on the plane of the line 4 4 of Fig.1, with some parts broken away, and in part on the line 4a-4 of Fig. 1;

Fig. 5 is a transverse sectional viewin two planes as indicated by thedotted line 5-5 of Fi 3;

ig. 6 is a transverse sectional view on the line 6 6 of Fig. 1;

Fig. 7 is a sectional View of thespring seat cutting through the axisthereof;

Fig. 8 is an elevation of the central friction element;

Fig. 8a is a sectional view on the line 8a-8a of Fig. 8;

Fig. 9 is an elevation of one of a portion of thrust wedging members;

Fig. 10 is a sectional View partly in elevation taken on the line 10-10of Fig. 9;

Figs. 1l and 12 are respectively side and end views of one of a pair ofwedging shoes; and

Figs. 13 and 14 are similar views of one of a pair of wear compensatingwedging elements.

The embodiment of the invention illustrated comprises a plate followerand a chambered follower or casing 21; a central unit generallydesignated A and consisting of a pair of groups of wedging elements anda central friction element 22 hereinafter referred to as a drag member;helical springs 23 (a pair of nested springs being shown) enclosedwithin the casing 21 and reacting between its closed end and a springseat 24 having the character of a follower; and two groups ofintercalated friction plates generally designated, respectively B and C,located between the unit A and the side walls of the casing The centralunit A comprises a pair of thrust wedging elements 25, 26, which seatagainst the follower 20. The adjacent faces of these elements are at andreceive between them and constantly frictionally engage the central dragelement 22. Each of the elements 25, 26, one 60 of which is shown indetail in Figs. 9 and 10, consists of an end block 27 having its innerface forwardly and inwardly inclined forming an obtuse wedging face 28,and a pair of arms 29, 30 extending forwardly from the end portions 6,5of the face 28, each arm carrying at its inner end an integral laterallyprojecting block 31, 32, having Wedging faces 33, 34,' parallel with theface 28. Y

The unit A further comprises a pair of wedge 7,0 blocks 35, 36, whichseat against a forwardly projecting stem 37 of the spring seat 24. Thefaces of these blocks, opposite to their `seating faces, are providedwith oppositely inclined wedging faces 33, 39, the former beingcomplementary-of and engaging the wedging faces 33, 34 of the blocks 31,32 for the purpose of urging these blocks and the arms 29, 30 carryingthem into engagement with the friction element 22. The wedging faces 39are oppositely inclined relatively to the wedging faces 38. The inner orseating face 39a of the element 35 is preferably somewhat inclined asshown in Figs. 1 and 14 toV facilitate release, the stem 37 beingprovided with Acomplementary seats.

Seated between the Wedgngface 28 of each of the elements 25, 26 and thewedging face 39 of each of the elements 35, `36'is a wedging shoe 40,41. The outer faces of these shoes are flat and the marginal portions oftheir inner faces are `cut away, as indicated at 42, to accommodate thearms 29, 30, leaving a central boss 43 which slidingly ts between thesearms, thereby holding the parts in assembled relation. 95

The two groups B, C, of intercalated friction plates are alike, eachcomprising a setof plates 44, 45 and 46 which are anchored to the casing21 against longitudinal movement relatively thereto, but are free to-m0ve laterally, and plates 47, 48 which float between the anchoredplates.Y

As shown, the plates of the former set are three in number and of thelatter, two. The number employed may be varied actually or relatively,as may be found expedient.

The plates 44, 45, 46 are shorter than their companion plates, and areshown as located adjacent the open end of the casing 241. Each of theseplates is provided adjacent its inner en d with laterally projectingwings 49 (Figs. 3 and 8) which engage shoulders 50, formed on the casing21, and locking bars 51 tted within the casing and held in place bymeans of ribs 51a, thereon. rEhe bars 51, 5l, but for convenience inassembling and replacement, might be made as integral ribs of thecasing.

The oating plates 47 and 48 in the release position of the gear bearagainst the spring seat 24 and project a considerable distance beyondthe casing, as shown in Fig. 1, terminating, however, short of thefollower 2i). y

The shorter plates are of greater width than the longer ones and areprovided along their side faces with shoulders as shown at 52 againstwhich the lateral margins of the longer plates loosely fit, therebymaintaining the proper relation of the parts. One of the shorter plates,preferably the inner one 44, tapers towards its outer end, as plainlyshown in Fig. 1, thereby presenting wedging faces to the outer faces ofthe shoes 4U, 4l, which are correspondingly inclined.

The central friction element 22v is preferably in the form of a plate,its inner end projecting through a slot in the spring seat-24, and beingprovided with laterally projecting wings as 53 (Figs. 4 and 8) whichseat in lateral eXtensions of the slot in the spring seat extending onlypartly therethrough. The plate is thereby prevented from withdrawal fromthe casing while the spring 23 prevents its inward movement relativelyto the seat.

Preferably, the member 22 is provided with a number of perforationswhich are lled with metal plugs 54 of an alloy, such as brass or bronze,having a lower coefficient of friction than the metal of which the plateis formed to insure a smoother action.

The element 22 is somewhat wider than the wedge members of the centralunit of the gear in order that it may extend into recesses as 55, formedin the members 51, whereby it is maintained in central position.

Where nested springs are employed, the inner one 56 may be held incentral position by means of a boss 5'7 on the face of the spring seat24. Ribs, indicated at 58, formed in the casing walls serve as guidesfor the outer spring. y.

For convenience in assembling and replacement of parts, a pair of alinedapertures 59, 60 are formed in opposite walls of the casing 21, theiraxes being back. ofthe normal position ofthe front face of the springseat 24. By inserting pins (not shown) -in these holes after the springhas been-sufficiently compressed to clear them, the spring and seat areretained upon release of the pressure.

In assembling the gear, the springs are first inserted. The centralfriction element 22 is placed'within the slot inthe spring 'seat 24, andthese parts are now inserted in the casing and forced inwardly againstthe resistance Aof the springs to clear the holes 59, 60 into which pinsare entered for temporarily maintaining the springsunder compression.The shorter plates are introduced and moved laterally against the sideof the casing. The Vcentral wedging elements are now inserted. The bars51, 51 are then placed in position; the shorter plates are spread apart;the shoes are entered; and the longer plates inserted.

Pressure now being applied to move inwardly the wedging elements tostill further compress the springs, the pins in the holes`59, 60, are

relieved from the spring pressure and may be withdrawn. The parts willnow assume their normal positions and will be held in place, theshoulders 31, 32 on wedge members 25 and 26 engaging the bars 5l, 5l,limiting release travel.

The operation of the gear is the same in the buff and draft. In buff,the thrust elements 25, 26 being moved inwardly, advance the shoes, andthe blocks 35, 36. This initial movement causes the compression of thesprings, the wedging elements of the central unit acting as a pair ofcolumns, the friction between the elements 25, 26 and plate 22contributing to the advance of the latter. As the shoes advance, theyare forced laterally inward by the weclging plates 44, 44, therebycrowding the blocks 35, 36 forward and further advancing the spring seatwhich carries the plate 22 with it against the resistance of itsfriction with the elements 25, 26. rEhe inward movement of the springseat moves it away from the longer plates 42', 48. When theA follower 20comesy into engagement with the latter plates, they are forced inwardly.The compression of theplates due to the wedging action develops highfriction between the two sets and largely absorbs the shocks.

As in draft gears'generally, the springs absorb the shocks to the extentof their capacity, but the limited space available prevents the use ofsprings of sufficient size and strengthto save the casing from burstingstresses, unless very heavy castings are employed. In thergear hereindisclosed, this spring vresistance is supplemented by the greaterfrictional resistance between the plate 22 and the elements 25,V 26,thereby reducing the lateral pressure. The lighter shocks are absorbedby the friction between the various parts of the central unit, the shoesand the tapering plates and the springs which continue to act during theheavier shocks and, in addition, high frictional resistance is developedby the movement of the floating plates relatively to the anchoredplates.

Upon release, the central unit is carried back, relatively to the casingby the spring pressure, relieving the wedging action of the shoes uponthe tapering plates. A too free release, however, is prevented-,by theslight wedging action of the blocks 35, 36 and of the shoes upon theelements 25, 26, urging the latter against the plate 22. The backwardmovement of the elements 25, 26 is less than the movement of the plate22, whichever isretarded by the friction between these parts, thusinsuring a somewhat retarded and smooth release, V,the use of the insets54 being a contributory factor.

The release may be further retarded by slightly inclining the contactingfacesA of the Wedge members 35, 36 with the stem 37 of the spring seat,as shown. The follower 24 having been carried away from the plates 47,48 upon the compression of the gear, there is no friction developedbetween these plates andrtheir associated plates at the commencement ofthe release, and when the spring seat overtakes the longer plates, thewedging compression thereon will have been supiiiciently relieved topermitY them to move outwardly without material retarding friction. Theparts come to rest when the shoulders 31, 32 reach the bars 51. Y 7

In draft, the casing 21 moves forwardly, th elements 25, 26 remainingstationary. The relative movements of all of the elements are, however,the same as in buff.

. The wedge-blocks 35, 36 and the wedging faces of the elements 25, 26cooperating with the shoes compensate for the Wearing of the parts,

the spring pressure in cooperation with the wedging action of the faces33, 34 of the elements 25, 26, and 38 of the blocks causing the latterto move outward laterally as wear occurs, insuring a continuous intimatecontact of "all of the elements of the gear without appreciablylessening the initial force of the springs.

The resistance to both compression and release may be varied through awide range by changing the pitch of the various wedging faces.

The disclosed embodiment of the gear has been found to be highlyefficient, but various changes may be made in it within the scope of theinvention.

I claim as my invention:

l. In a draft gear, in combination, a pair of opposed followers, onethereof being chambered, groups of intercalated friction plates inclosedwithin the chamber, the inner plate ofA each group being tapered towardits outer end, a spring seated against the closed end of the chamberedfollower, a spring seat engaging the opposite end of the spring, acentral unit intei-posed between the other follower and the last-namedspring seat, such unit comprising a pair of Wedging thrust membersengaging the follower, a pair of wedging thrust members associated withthe seat, a pair of wedging shoes interposed between the outer and innerthrust members and bearing upon the tapering plates, and a drag plateanchored to the seat and frictionally engaging the first named thrustmembers.

2. In a draft gear, in combination, a pair of opposed followers, onethereof being chambered, friction plates housed within the casing and atopposite sides thereof and being relatively longitudinally movable,acute wedging elements laterally bearing upon the plates, friction shoesengaging such wedges and having obtuse wedging faces at their ends, apair of thrust wedge members cooperating with the outer ends of theshoes, a pair of thrust wedge members cooperating with the inner end ofthe shoes, a spring seat bearing upon the second named thrust members, aspring reacting between the seat and the closed end of the chamberedfollower, and a drag plate anchored to the seat and slidable between thefirst named thrust members.

3. In a draft gear, in combination, a pair'of opposed followers, onethereof being chambered, friction plates housed within the chamber andat opposite sides thereof and being relatively longitudinally movable,acute Wedging elements laterally bearing upon the plates, friction shoesengaging such wedges and having obtuse wedging faces at their ends, apair of thrust wedge members cooperating with the outer ends of theshoes, a pair of thrust wedge members cooperating with the inner ends ofthe shoes, a spring seat bearing upon the second named thrust wedges,the contacting faces of such parts being inclined outwardly and towardthe seat, a spring reacting between the seat and the closed end of thechambered follower, and a drag plate anchored to the seat and slidablebetween the rst named thrust members.

4. A pair of opposed followers, one thereof being chambered, a movablespring` seat enclosed within the chamber, a spring reacting between theinner end of the chamber and the seat, a group of intercalated frictionplates at each side of the chamberV and adjacent the outer end thereof,the inner plate of each group being tapered toward its outer end,friction shoes engaging the tapered plates, thrust wedge means engagingthe outer ends of the shoes, thrust wedge means engaging the inner endsof the shoes and the seat and having wedge yfaces engaging outwardly andbackwardly inclined Wedg- 100 ing faces of the seat.

5. In a draft gear, in combination, a casing,

a spring seated against the inner end of the casing, a movable springseat engaging the opposite end of the spring, two groups of intercalatedfriction plates within the casing, two sets of longitudinally arrangedwedging elements interposed between the groups of plates and bearings ascolumns upon the spring seat, and a drag plate anchored to the springseat and located between the two sets of wedging elements and resistingthe lateral reaction thereof, the drag plate being in direct engagementwith certain of the wedge elements.

6. In a draft gear, in combination, a chambered follower, a spring seatwithin the follower, a spring reacting between the seat and the innerend of the follower, a central friction plate anchored to the seat, anopposed follower, two groups of intercalated friction plates, one set ofeach group being anchored to the chambered follower and the other setbeing engageable by the spring seat on release, a pair of wedgingfriction shoes, one interposed between each group of plates and thecentral plate, wedge means associated with the seat for applyingspreading pressure to the shoes, and a pair of thrust members seatedagainst the opposed follower and frictionally engaging the central plateand having wedging faces cooperating with the shoes.

HERBERT E. TUCKER.

